The Layer Two Tunneling Protocol (L2TP) is a protocol used by both Internet Service Providers (ISPs) and Virtual Private Networks (VPNs). The prowess that L2TP can leverage for connectivity is of interest to VPNs, while ISPs can foster VPN operations with it.
L2TP is the outcome of combining two older protocols: Microsoft’s Point-to-Point Tunneling (PPTP) and Cisco’s Layer 2 Forwarding (L2F). The hybrid result, L2TP, combines the best of both worlds and improves upon them significantly. The protocol was born as the last century ended to replace earlier protocols. Technically, it’s the standard RF C26661.
Here’s what you need to know about L2TP:
- It needs to be paired with another protocol to maximize its benefits.
- It’s usually paired with IPSec, which brings security to the data load.
- The combination of L2TP and IPSec opens up a broad spectrum of possibilities regarding security features because it enables the use of AES 256-bit and the 3DES algorithm.
- L2TP’s packets feature double encapsulation, which improves their security. However, it also makes the protocol more taxing on the equipment.
- L2TP’s port of choice is 1701. But once IPSec comes into the mix, various other ports can become alive. For instance, port 500 will manage the Internet Key Exchange (IKE), 4500 for NAT, and 1701 (the original one) for L2TP traffic.